Polymer powder bed fusion surface texture measurement

Marc-Antoine de Pastre (1) , Adam Thompson , Yann Quinsat (1) , Albajez García , Nicola Senin (2) , Richard Leach (2)

1 LURPA - Laboratoire Universitaire de Recherche en Production Automatisée
2 UON - University of Nottingham, UK

Polymer laser powder bed fusion (LPBF) surfaces can be challenging to measure. These surfaces comprise complex features including undercuts, deep recesses, step-like transitions, a large range of measurement scales and unfavourable optically materials properties. While recent research has begun to examine the nature of these surfaces, there has not yet been significant effort in understanding how different measurement instruments interact with them. In this paper, we compare the results of LPBF surface topography measurements using a series of different instrument technologies, including contact stylus, focus variation microscopy, coherence scanning interferometry, laser scanning confocal microscopy and X-ray computed tomography. Measurements are made on both side and top surfaces of a cubic polyamide-12 LPBF sample. Different instrument behaviours are highlighted through qualitative visual inspection of surface reconstructions. Further comparisons are then performed through evaluation of profile and areal surface texture parameters and statistical modelling of surface topographies. These analyses allow for the identification both of discrepancies between texture parameters and discrepancies between local topographies reconstructed from measurements. Instrument repeatability metrics are also presented for each measurement of the test surfaces. Results show that discrepancies in measurements made on the acquired datasets are often similar in magnitude to the size of the features present on the surfaces. Conclusions are drawn regarding the suitability of various surface measurement instruments for polymer LPBF surfaces.

Mots clés: additive manufacturing; polymer powder bed fusion; surface metrology; data comparison

Domaines: Génie mécanique [physics.class-ph]

Marc-Antoine de Pastre, Adam Thompson, Yann Quinsat, Albajez García, Nicola Senin, et al.. Polymer powder bed fusion surface texture measurement. Measurement Science and Technology, 2020. ⟨hal-02434359⟩